The inventive concepts described herein generally relate to semiconductor memories, and more particularly, to an operating method of a memory system which includes a NAND flash memory, a variable resistance memory, and a controller.
A semiconductor memory device is a data storage device which is fabricated using semiconductors such as silicon (Si), germanium (Ge), gallium arsenide (GaAs), indium phosphide (InP), and the like. Semiconductor memory devices are generally classified as either volatile memory devices or nonvolatile memory devices.
The volatile memory devices are generally characterized by the loss of stored contents upon a power-off state. Some examples of volatile memory devices include static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), and the like. In contrast, nonvolatile memory devices are generally characterized by the retention of stored contents when power is turned off or otherwise disconnected. Examples of nonvolatile memory devices include read only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable and programmable ROM (EEPROM), flash memory device, phase-change RAM (PRAM), magnetic RAM (MRAM), resistive RAM (RRAM), ferroelectric RAM (FRAM), and the like. Among these, flash memory is typically configured as either NOR type flash memory or a NAND type flash memory.